A study of the prevalence of early onset periodontitis in U.S. children aged 14 to 17 years has been completed and was published in October, 1991. In a national survey, the total number of adolescents affected by LJP was about 70,000. Seventeen thousand were estimated to have GJP and another 212,000 adolescents had incidental LA (greater than or equal to 3mm on 1 or more teeth). Blacks were at greater risk of all forms of early onset periodontitis than whites. Males were more likely (4.3 to 1) to have GJP than females when other variables were statistically controlled. A major contract to relocate, re-examine and collect risk factor information on these children began in October, 1991. Research objectives are to: a) assess the progression of periodontal destruction among the cases of early onset periodontitis, b) characterize the microbial ecology of the sub-gingival plaque among persons with early onset periodontitis, and c) compare the presence and concentration of selected putative pathogens and high-resistance factors among individuals with early onset periodontitis to controls. A sample of all cases whose oral examinations from the 1986-87 survey indicated early onset periodontitis or other severe periodontal problems was selected for study. Two controls per case matched by age, gender, race and geographic location were also located and invited to participate in the study. During FY'93, examinations were made on approximately 265 young people 19-25 years of age. Full mouth oral examinations for periodontal measures and dental caries were conducted. Biological specimens, blood, gingival crevicular fluid and subgingival plaque fluid were also collected. A questionnaire including such variables as medical history, family history, and dental utilization was administered at the time of the oral exam. Laboratory analyses of biological specimens is under way. Dental examination data is being edited and prepared for analysis.